Diameter protocol is a protocol widely applied in the networks of Policy Control and Charging PCC (Policy Control and Charging) Architecture and Long Term Evolution LTE (Long Term Evolution), network interconnection protocol IP (International Protocol) Multimedia Subsystem IMS (IP Multimedia Subsystem) in 3G (3rd-Generation, the 3rd mobile communication system) networks. Arranged in a Diameter network is a Diameter message Routing Agent DRA (Diameter Routing Agent) which supplies a message routing function of Diameter signaling, and can achieve centralized forwarding of Diameter signaling in a multi-network architecture.
During the process of forwarding of Diameter signaling in DRA, according to current Diameter protocol, supposing that there are two routings from DRA1 to a Diameter master server including:                Routing 1: DRA1-DRA2-Diameter master server        Routing 2: DRA1-DRA3-Diameter master server        
Upon reception of a message required to be sent to the Diameter master server, according to routing priority, Routing 1 is firstly selected to send this message. If the link from DRA2 to the Diameter master server is faulty at this time, it is impossible for the message to be delivered to the Diameter master server, namely Routing 1 is inaccessible. At this time, DRA1 may receive an error response “DIAMETER_UNABLE_TO_DELIVER” from DRA2, and resend the message through routing 2. During the period when the link from DRA2 to the Diameter master server is faulty, if DRA1 again receives a message required to be sent to the Diameter master server, it may still select Routing 1 for sending, and resend the message after an error response from DRA2 is received.
The aforementioned method of signaling forwarding may result in the fact that the message is frequently sent by DRA1 on a faulty routing, which not only wastes the capacity of the link, but also increases message forwarding time delay and affect a user's business experience.